Type 1 Diabetes Biomarkers

ABSTRACT

Type 1 diabetes (T1D) patients make antibodies to self-proteins that are potential biomarkers for early detection and risk prediction. We have identified seventeen antigens as biomarkers for early diagnosis and risk prediction of T1D, including the antigens MLH1, MTIF3, PPIL2, NUP50, TOX4, FIGN, C9orf142, ZNF280D, HES1, QRFPR, CTRC, SNX6, SYTL4, ELA2A, IGRP, PAX6, and HMGN3.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/100,775, filed Jan. 7, 2015, the entire contents of which areincorporated herein in their entirety by reference.

FIELD OF THE INVENTION

This disclosure relates to biomarkers for the prediction of Type 1diabetes (T1D) onset and for diagnosing T1D.

BACKGROUND OF THE INVENTION

T1D is one of the most common juvenile autoimmune diseases. It ischaracterized by progressive autoimmune destruction of pancreatic betacells. The incidence of T1D is increasing worldwide. T1D patients aredependent on lifelong exogenous insulin but this is not a cure and inthe long term there are serious co-morbidities. This leads to bothpersonal and societal burdens in terms of financial and quality of lifeindicators. At the time of T1D diagnosis, it is thought that potentially70%-90% of pancreatic beta cells have been destroyed. Therefore earlydiagnostic and prognostic markers of T1D prior to symptomatic diseaseonset will be of great value in identifying individuals that couldbenefit from intervention protocols while significant beta cell functionstill exists.

Prevention of T1D will only be possible if individuals with high riskfor progression to T1D can be identified. The incidence of T1D ingeneral population is around 22/100,000 in the US. The majority of T1Dcases are diagnosed in non-relatives with 85% of new T1D cases occurringin individuals with no known family history. Thus, biomarkers are neededto improve our prediction models and enable the selection of subjectswith, for example, high 5-year risk of disease onset. Such markers couldbe deployed immediately to identify high-risk subjects for interventiontrials. Additionally in differentiating type 1 diabetes from other formsof diabetes mellitus autoantibodies are helpful and yet there are stillsome individuals with T1D that are negative for the current knownautoantibodies, thus the discovery of additional autoantibodies aids inthe differential diagnosis of T1D.

SUMMARY OF THE INVENTION

Identifying markers that present prior to the development of ourcurrently used autoantibodies (AAbs) could improve the risk predictionmodels. Thus, the embodiments disclosed herein relate to theidentification of AAb biomarkers in T1D so as to increase thesensitivity of detection in T1D patients and improve the T1D riskprediction model.

All references disclosed throughout are hereby incorporated herein intheir entirety.

In one embodiment, we used a novel protein microarray technology termed“Nucleic Acid Programmable Protein Array” (NAPPA) (see, e.g., EP1360490B1). This innovative protein microarray format avoids the need toexpress and purify the proteins by substituting the printing of fulllength cDNAs on the arrays. Proteins corresponding to the cDNAs areproduced in situ as needed at the time of the assay by in vitrotranscription and translation (IVTT)-coupled cell lysates. The cDNAs areconfigured to append a common epitope tag to all of the proteins ontheir C-termini so that they can be captured by a high-affinity capturereagent that is immobilized along with the cDNA.

In another embodiment, a method of diagnosing Type 1 diabetes onsetincludes the step of contacting an antibody-containing fluid sample froma subject with one or more of antigens selected from the groupconsisting of MLH1, MTIF3, PPIL2, NUP50, TOX4, FIGN, C9orf142, ZNF280D,HES1, QRFPR, CTRC, SNX6, SYTL4, ELA2A, IGRP, PAX6, and HMGN3, whereindetection of antibodies with a suitable detection agent to one or moreof these antigens indicates a diagnosis of Type 1 diabetes onset incomparison to a healthy control sample.

In a further embodiment, a method of screening for a risk factorassociated with Type 1 diabetes onset includes the step of contacting anantibody-containing fluid sample from a subject with one or moreantigens selected from the group consisting of MLH1, MTIF3, PPIL2,NUP50, TOX4, FIGN, C9orf142, ZNF280D, HES1, QRFPR, CTRC, SNX6, SYTL4,ELA2A, IGRP, PAX6, and HMGN3, wherein detection of antibodies with asuitable detection agent to one or more of these antigens indicates anelevated risk of Type 1 diabetes onset in comparison to a healthycontrol sample.

These and other aspects of the embodiments disclosed herein will beapparent upon reference to the following disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts jitter plots of representative autoantigens fromscreening and knowledge based approaches (T1D stands for new-onset T1Dpatients; HC stands for healthy controls).

DETAILED DESCRIPTION OF THE INVENTION

The embodiments disclosed herein relate to 17 antigens that have beenidentified as biomarkers for early detection and risk prediction of T1D.These antigens are: MLH1, MTIF3, PPIL2, NUP50, TOX4, FIGN, C9orf142,ZNF280D, HES1, QRFPR, CTRC, SNX6, SYTL4, ELA2A, IGRP, PAX6, and HMGN3.

In general, two approaches were used to discover the disclosed antigens:a screen based approach and a knowledge based approach. To profile theserological antibody response, 40 T1D patients and 40 age/gender matchedhealthy controls were screened against 10,000 human proteins across 5NAPPA array sets.

40 antigens were chosen for enzyme-linked immunosorbent assay (ELISA)verification on the same sample set. 19 antigens verified by ELISA wereprocessed to the validation stage with 60 T1D patients and 60 healthycontrols. In the knowledge based approach, 126 pancreas enriched geneswere selected from literature mining and bioinformatics analysis andmeasured for their sero-reactivity among 46 T1D patients and 46 healthycontrols. 15 antigens were chosen for validation in 50 T1D patients and50 healthy controls.

Kits for assessing the presence of antigens for Type 1 diabetes are alsocontemplated. An exemplary kit includes an antigen selected from MLH1,MTIF3, PPIL2, NUP50, TOX4, FIGN, C9orf142, ZNF280D, HES1, QRFPR, CTRC,SNX6, SYTL4, ELA2A, IGRP, PAX6, and HMGN3 to test serologicalantibodies, as well as a suitable detection agent (e.g., a labeledsecondary antibody).

Example

Sera from T1D patients contain AAbs to human self-proteins. Thus, thesero-reactivity to 10,000 human proteins with sera from T1D patients andmeasured bound IgG. We scaled down the candidate number for validationin an independent sample set. In the knowledge based approach, weperformed ELISA on 126 pancreas enriched genes and validate thecandidates in an independent sample set. Taken together, 17 potentialautoantigens were identified with sensitivities ranging from 10-27% at95% specificity (Table 1).

Rapid antigenic protein in situ display (Rapid) ELISA was performed toconfirm the sensitivities of autoantibodies biomakers. 96-well ELISAplates (Corning, Me.) were coated with 10 ng/mL anti-glutathioneS-transferase (GST) antibody (GE Healthcare, Pa.) in coating buffer (0.5M carbonate bicarbonate buffer, pH 9.6) overnight at 4° C. On the nextday, coated plates were washed 3 times with PBST and blocked with 5%milk-PBST (0.2% Tween) for 1.5 hrs at room temperature (RT).

Meanwhile, 40 ng/μL plasmids encoding candidate autoantigens wereexpressed in the human Hela cell-lysate based expression system at 30°C. for 1.5 hrs. After expression, candidate autoantigens were diluted inmilk-PBST and captured in ELISA plates at 500 rpm for 1 h at RT. Plateswere washed 5 times with PBST and incubated with diluted serum samplesat 500 rpm for 1 h at RT. Then plates were washed again and incubatedwith HRP labeled anti-human secondary antibody (Jackson ImmunoResearchLaboratories, Pa.) for 1 h.

Finally, the plates were washed and incubated by 1-Step Ultra TMB—ELISASubstrate (Thermo scientific, Ill.) for detection and sulfuric acid tostop the reaction. OD450 was measured by Envision Multilabel Reader(Perkin Elmer, Mass.). Expression of candidate autoantigens wasconfirmed by mouse monoclonal anti-GST primary antibody and HRP labeledanti-mouse secondary antibody detection on the same plate. Relativeabsorbance was obtained by using the raw ELISA data dividing by themedium signal of each sample across all the antigens tested on the sameday. The sensitivities for each antigen were determined at 95%specificity in comparison to a healthy control sample.

Prior work indicated that there are four known AAb biomarkers identifiedin T1D. The 5-year risk for T1D is 20-25% for subjects with one AAb,50-60% for subjects with two AAbs, near 70% for subjects with three AAbsand 80% for those with four AAbs. Additional AAb biomarkers will help toimprove the risk prediction in the general population. Thus, forexample, the presence of autoantibodies to the antigen proteins asdisclosed herein could be tested by immuno-assays. The presence of oneor more autoantibodies disclosed herein could be used as prediction ofT1D onset.

The embodiments and example described above are not intended to belimiting.

TABLE 1 Discovery and Validation Statistics for 17 T1D biomarkersDiscovery Validation All Sensi- Specif- Sensi- Specif- Sensi- Specif-Antigen tivity icity tivity icity tivity icity MLH1 0.15 0.95 0.33 0.950.27 0.95 MTIF3 0.15 0.95 0.20 0.95 0.25 0.95 QRFPR 0.13 0.95 0.06 0.950.20 0.95 PPIL2 0.20 0.95 0.18 0.95 0.19 0.95 NUP50 0.15 0.95 0.17 0.950.16 0.95 CTRC 0.17 0.95 0.08 0.95 0.15 0.95 SNX6 0.13 0.95 0.04 0.950.15 0.95 TOX4 0.20 0.95 0.12 0.95 0.13 0.95 FIGN 0.13 0.95 0.12 0.950.13 0.95 SYTL4 0.20 0.95 0.02 0.95 0.13 0.95 ELA2A 0.11 0.95 0.04 0.950.13 0.95 C9orf142 0.18 0.95 0.05 0.95 0.11 0.95 ZNF280D 0.13 0.95 0.080.95 0.11 0.95 HES1 0.10 0.95 0.15 0.95 0.11 0.95 IGRP 0.17 0.95 0.020.95 0.11 0.95 PAX6 0.15 0.95 0.08 0.95 0.11 0.95 HMGN3 0.28 0.95 0.080.95 0.10 0.95

What is claimed is:
 1. A method of diagnosing Type 1 diabetes onset,comprising the step of contacting an antibody-containing fluid samplefrom a subject with one or more of antigens selected from the groupconsisting of MLH1, MTIF3, PPIL2, NUP50, TOX4, FIGN, C9orf142, ZNF280D,HES1, QRFPR, CTRC, SNX6, SYTL4, ELA2A, IGRP, PAX6, and HMGN3, whereindetection of antibodies with a suitable detection agent to one or moreof these antigens indicates a diagnosis of Type 1 diabetes onset incomparison to a healthy control sample.
 2. A method of screening for arisk factor associated with Type 1 diabetes onset, comprising the stepof contacting an antibody-containing fluid sample from a subject withone or more antigens selected from the group consisting of MLH1, MTIF3,PPIL2, NUP50, TOX4, FIGN, C9orf142, ZNF280D, HES1, QRFPR, CTRC, SNX6,SYTL4, ELA2A, IGRP, PAX6, and HMGN3, wherein detection of antibodieswith a suitable detection agent to one or more of these antigensindicates an elevated risk of Type 1 diabetes onset in comparison to ahealthy control sample.
 3. A kit for assessing the presence of antigensfor Type 1 diabetes, comprising an antigen selected from the following:MLH1, MTIF3, PPIL2, NUP50, TOX4, FIGN, C9orf142, ZNF280D, HES1, QRFPR,CTRC, SNX6, SYTL4, ELA2A, IGRP, PAX6, and HMGN to profile serologicalantibodies, and a suitable detection agent.